Article by Kevin Savetz

First Published:
Date Published:
Copyright © by Kevin Savetz

November 3, 1997

This issue we'll explore the world of computer viruses and how you can keep them at bay. What you don't know about them can hurt you, so read on.

If your hard drive was wiped clean today, what information would you lose? Vital business contracts, your saved Quake game, web bookmarks, an unfinished letter to Mom? How long would it take you to restore from backups (you DO have backups, right?) and get your computer back to normal? Most of us would rather not know the answers to these questions. However, all it can take to turn these posits into brutal reality is a visit from a nasty little program called a virus.

A computer virus is a program, named for its organic counterpart, that infects files on a computer system. When you run an infected program, the virus spreads by coping itself to other files on your hard drive. Many viruses are programmed to wait for a certain period -- after it has made a number of copies of itself, or until a certain date -- before doing damage. A malicious virus might be programmed to erase the files on your hard disk, a more benign one might annoy you by printing strange messages on your screen. Other viruses don't perform overt actions; instead they silently propagate from file to file, and from computer to computer. Even seemingly benign viruses can cause problems because they modify existing information on your disk. A bug in the code of a "harmless" virus can prove as disastrous as an overtly malicious one.

Why should you worry about viruses? Because it only takes one to ruin your data and your day. And there are a lot of different viruses out there: more than 10,000 DOS viruses, a dozen Windows-specific strains, and 35 Macintosh viruses. There are also some 200 cross-platform "macro viruses," baddies that hide in documents of applications with powerful macro languages, such as Microsoft Word and Excel.

Your computer can catch a virus in a number of ways. Most common for Internet users is to download an infected program. Offline users aren't safe, either. Your hapless machine can catch a virus by running a program on a borrowed floppy disk or from another computer in your local area network.

Computer viruses are analogous to the human variety -- some cause a mild case of the sniffles, others are more dire. "You don't want your computer to get a virus, the same way you don't want one. That means knowing your partners well. Don't just pick up software off the streets," Sharon Fisher, Senior Analyst for Gartner Datapro, says. Practicing "safe hex" is even easier than safe sex, since anti-virus software can check for unwelcome intruders before it's too late.

It may all sound overwhelming, but preventing viruses simply takes methodical care. "The threat of viruses is quite manageable if you don't install a lot of software of uncertain origin, and if you follow some simple rules: if you download software from the Internet, get it directly from the manufacturer's web or FTP server, or from one of the major software archives," says John Levine, co-author of The Internet For Dummies. "On the other hand, if you download random stuff from sites that say 'WAREZ D00DZ', you deserve what you get."

Can you get a virus by reading an electronic mail message? Despite dire warnings that have been posted to the Net for years, your computer cannot catch a virus simply by reading an e-mail message from a stranger. "E-mail as e-mail presents no virus threat, since viruses live in programs and e-mail is data," Levine says. However, "If an e-mail message contains an attached program, treat that with the same scepticism you'd use for any other downloaded program. Consider where it came from, and use an up-to-date virus checker if you're not sure."

As the saying goes, an ounce of prevention is worth a pound of cure. A little inoculation against viruses goes a long way towards preventing misfortune.

Anti-Virus software

A variety of software, both commercial and freeware, is available that can help protect your computer. Two of the most popular commercial anti-virus packages for Windows are Dr. Solomon's ( and F-PROT ( Free software includes the well-regarded EliaShim's ViruSafe Web 3.0 ( for Windows 3.x, 95, and DOS.

The most popular freeware virus tool for Macintosh users is Disinfectant. Offering the basics of disk scanning and eradication, Disinfectant is simple but effective. It is available from the Info-Mac HyperArchive ( Commercial entries include Symantec AntiVirus for Macintosh, a powerful tool that scans for macro viruses, allows scheduled scans and offers free updates (

Two features available in most anti-virus software are the ability to scan your hard drive for viruses (something you should do regularly) and to intercept a virus should you run an infected program. More advanced features include the ability to scan software as it downloads, scan a network for viruses, and search for Trojan horses. All anti-virus software worth its weight in bits will prevent viruses from acting -- and should one slip through the cracks (or if your computer caught a virus before you run the anti-virus software) will eradicate the malarious strain from your system.

Anti-virus software is only as good as its information about viral strains. New viruses are written all the time. If your anti-virus program doesn't know the traits of a virus, it may not be able to stop its spread. So it is important to keep your anti-virus software up to date. This is where the commercial virus inhibitors shine. Many commercial programs include a subscription to virus definition updates. These are info files, delivered via snail mail or the Internet, that tell the software how to look for new viruses. If you opt for freeware, the burden is on you to make sure you always have the latest version of your virus software.

"What's important is isn't the particular software that someone uses, but that they use something and that they keep it updated because there are always new viruses," Fisher says.

If you have data that you need to protect -- even if you make frequent backups -- you need to get and use an anti-virus tool. Use one of the excellent free tools or invest in a more robust commercial program. Anti-virus tools are an unfortunate necessity in today's computing world -- and will remain so until the miscreant hackers of the world get lives and stop creating viruses.


PC free anti-virus software:

EliaShim's ViruSafe Web:

PC commercial anti-virus software:

Dr. Solomon's:


McAfee VirusScan:

Macintosh free anti-virus software:


Macintosh commercial anti-virus software:

Symantec AntiVirus for Macintosh:

Articles by Kevin Savetz